Expert: Walter Hintz - 3/18/2007

Question
How is the presence or absence of cephalization suitable to the way animal acquires food?
Respiratory organs in the crayfish and the grasshopper, how are these suitable to the habitat of each?


Answer
Hi Kim; Sorry for the late answer but I was on vacation.  It should have been noted at allexperts
  Cephalization refers to the formation of a head. Animals with a gut have a head.  If not they would have to phagasitize food (like an amoeba) or absorb it

Respiratory organs in aquatic animals must be designed to extract O2 from the water.  The crayfish has gills with a large surface area since the O2 content in water is less then in the air.  Grasshoppers have openings in the abdomen that allows the passage of atmospheric O2 directly into the body fluids.  Atmospheric O2 is 21 % and less surface area is needed.